The present invention relates to generally to Ethernet ports and the serial-to-Ethernet conversion associated with such ports. More particularly, the invention relates to the structure and method of fabrication of a serial-to-Ethernet converter housed completely within an Ethernet jack to provide profile reduction, and reduce manufacturing cost and complexity. Furthermore, the serial-to-Ethernet converter also contains general purpose programmable input/output pins (PIO). These PIOs can be used to control devices that have no microcontroller, and also read data from such devices. This integral RJ-45/converter device can thus be used as a complete modular Ethernet interface for electronic devices that lack intelligence (no microcontroller).
A Registered Jack-45 (RJ-45) is a wire connector used commonly to interface microcontroller based products onto local area networks (LAN), particularly Ethernets. RJ-45 connectors employ a male plug and a female jack or socket. The present invention concerns an improved RJ-45 Ethernet Jack that integrates functionality which is commonly required for an interface to electronic devices.
The RJ-45 jack characteristically is comprised of a housing incorporating a planar array of parallel electrical contacts for mating with the RJ-45 plug and its aligned electrical contacts. The jack contacts are typically spring contacts for biased engagement with the plug.
Microcontroller based products commonly use serial communication, and it is common to encode the serial communication in an RS-232 [EIA-232] format. It is therefore necessary to convert the serial protocol to Ethernet signals to allow LAN access. This is typically accomplished through a serial-to-Ethernet converter that takes the RS-232 encoded TTL data, and transparently translates the data to twisted-pair Ethernet protocol signals [10/100 Base-T]. In the prior art, signal translation and conditioning, such as the serial-to-Ethernet conversion, has been achieved through components mounted to a printed circuit board (PCB) adjacent to the RJ-45 jack or mounted on a PCB with the jack.
PCB components used in serial to Ethernet conversion include electronics such as general purpose microcontrollers, media access controllers, Ethernet physical layer devices (PHY), memory chips, voltage regulator chips, supervisory circuits, and various passive components (resistors, capacitors, inductors, and crystals). The PCB also typically includes adjacent status or diagnostic light emitting diodes (LEDs). In addition, the adjacent PCB typically includes components for electrical isolation, electrostatic discharge (ESD) protection, suppression of incoming interfering signals, and suppression of radiated and conducted interference. The components used for these purposes typically consist of magnetic isolation transformers and chokes, capacitors, and resistors. These are commonly referred to as the “magnetics”.
In known devices, the numerous electronic components associated with a serial-to-Ethernet conversion are connected to an RJ-45 connector jack through a series of printed or discrete wires or leads, either remotely or immediately adjacent the RJ-45 jack when the jack is mounted directly on the PCB board. Manufacturers have attempted to provide modular systems for Ethernet-to-serial conversion, however, in all instances the electronic circuitry associated with the conversion is mounted to a PCB board outside of the RJ-45 jack housing. Because of the standard arrangement of the RJ-45 jack and attendant electronic circuitry components, known systems require a substantial footprint which takes up critical limited space.
Connector manufacturers have attempted to place signal conditioning components and LEDs inside the bodies of connectors. For example, isolation and filtering magnetics have been placed within jack housings that have been extended at the back of the connectors to accommodate a PCB and windings. Status LEDs have been mounted in the front of the RJ 45 jack, and controlled through extra leads protruding from the bottom of the connector. An example of integrated LED components may be found at U.S. Pat. No. 4,978,317, the substance of which is incorporated herein by reference. In known devices, manufacturers have failed to place all of the components necessary for a complete conversion from serial to Ethernet within the standard jack housing. In this regard, manufacturers have failed to provide a modular RJ 45 jack with complete serial to Ethernet conversion.